refactored css, including some markup changes

app/templates/header/header.css

@@ -0,0 +1,104 @@
+.header {
+  align-items: flex-start;
+  box-sizing: border-box;
+  display: flex;
+  justify-content: space-between;
+  padding: 31px;
+  width: 100%;
+}
+
+.logo {
+  display: flex;
+  position: relative;
+  align-items: center;
+}
+
+.logo__link {
+  display: flex;
+  flex-direction: row;
+}
+
+.logo__title {
+  color: #3e3d40;
+  font-size: 32px;
+  font-weight: 500;
+  margin: 0;
+  position: relative;
+  top: -1px;
+  letter-spacing: 1px;
+  margin-left: 8px;
+  transition: color 50ms;
+}
+
+.logo__title:hover {
+  color: var(--primaryControlBGColor);
+}
+
+.logo__subtitle {
+  color: #3e3d40;
+  font-size: 12px;
+  margin: 0 8px;
+}
+
+.logo__subtitle-link {
+  font-weight: bold;
+  color: #3e3d40;
+  transition: color 50ms;
+}
+
+.logo__subtitle-link:hover {
+  color: var(--primaryControlBGColor);
+}
+
+.feedback {
+  background-color: var(--primaryControlBGColor);
+  background-image: url('../assets/feedback.svg');
+  background-position: 2px 4px;
+  background-repeat: no-repeat;
+  background-size: 18px;
+  border-radius: 3px;
+  border: 1px solid var(--primaryControlBGColor);
+  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.1);
+  color: #fff;
+  cursor: pointer;
+  display: block;
+  float: right;
+  font-size: 12px;
+  line-height: 12px;
+  opacity: 0.9;
+  padding: 5px;
+  overflow: hidden;
+  min-width: 12px;
+  max-width: 12px;
+  text-indent: 17px;
+  transition: all 250ms ease-in-out;
+  white-space: nowrap;
+}
+
+.feedback:hover,
+.feedback:focus {
+  min-width: 30px;
+  max-width: 300px;
+  text-indent: 2px;
+  padding: 5px 5px 5px 20px;
+  background-color: var(--primaryControlHoverColor);
+}
+
+.feedback:active {
+  background-color: #0277d8;
+}
+
+@media (max-device-width: 520px), (max-width: 520px) {
+  .header {
+    flex-direction: column;
+    justify-content: flex-start;
+  }
+
+  .feedback {
+    margin-top: 10px;
+    min-width: 30px;
+    max-width: 300px;
+    text-indent: 2px;
+    padding: 5px 5px 5px 20px;
+  }
+}

app/templates/header/index.js

@@ -0,0 +1,59 @@
+const html = require('choo/html');
+const assets = require('../../../common/assets');
+/*
+  The current weback config uses package.json to generate
+  version.json for /__version__ meaning `require` returns the
+  string 'version.json' in the frontend context but the json
+  on the server.
+
+  We want `version` to be constant at build time so this file
+  has a custom loader (/build/version_loader.js) just to replace
+  string with the value from package.json. 🤢
+*/
+const version = require('../../../package.json').version || 'VERSION';
+
+function browserName() {
+  try {
+    if (/firefox/i.test(navigator.userAgent)) {
+      return 'firefox';
+    }
+    if (/edge/i.test(navigator.userAgent)) {
+      return 'edge';
+    }
+    if (/trident/i.test(navigator.userAgent)) {
+      return 'ie';
+    }
+    if (/chrome/i.test(navigator.userAgent)) {
+      return 'chrome';
+    }
+    if (/safari/i.test(navigator.userAgent)) {
+      return 'safari';
+    }
+    return 'other';
+  } catch (e) {
+    return 'unknown';
+  }
+}
+
+const browser = browserName();
+
+module.exports = function(state) {
+  return html`<header class="header">
+  <div class="logo">
+    <a class="logo__link" href="/">
+      <img
+        src="${assets.get('send_logo.svg')}"
+        alt="Send"/>
+      <h1 class="logo__title">Send</h1>
+    </a>
+    <div class="logo__subtitle">
+      <a class="logo__subtitle-link" href="https://testpilot.firefox.com">Firefox Test Pilot</a>
+      <div>${state.translate('siteSubtitle')}</div>
+    </div>
+  </div>
+  <a href="https://qsurvey.mozilla.com/s3/txp-firefox-send?ver=${version}&browser=${browser}"
+    rel="noreferrer noopener"
+    class="feedback"
+    target="_blank">${state.translate('siteFeedback')}</a>
+</header>`;
+};